1. Field of the Invention
This invention relates to a method for reducing the microbial content of surfaces, and more particularly, to formulations containing an anhydrous complexes of PVP--H.sub.2 O.sub.2 for treating such surfaces.
2. Description of the Prior Art
Stabilized H.sub.2 O.sub.2 compositions have found wide utility in commercial and industrial applications, e.g. as antiseptics, disinfectants, sterilization agents, bleaching materials, washing concentrates, etchants, in cosmetic preparations, and as a catalyst in polymerizations requiring a free radical source. In biological applications which require an antiseptic, disinfectant or sterilization agent, such H.sub.2 O.sub.2 compositions require release of an effective amount of oxygen at a desired rate.
Shiraeff, in U.S. Pat. Nos. 3,376,110 and 3,480,557, discloses a solid, stabilized hydrogen peroxide composition of hydrogen peroxide and a polymeric N-vinyl heterocyclic compound prepared in an aqueous solution of the components. The process involved mixing predetermined amounts of PVP and aqueous H.sub.2 O.sub.2 and evaporating the solution to dryness. The Shiraeff composition, which was believed to be a solid, dry complex, was described as not necessarily anhydrous due to the hydrophilic nature of the PVP and the water present in the reaction solution. Shiraeff stated that water could be tolerated, however, if it did not affect the solid dry characteristics of the complexes. The H.sub.2 O.sub.2 content of the composition was given as being at least 2%, and preferably 4.5 to 70% by weight. Prolonged drying of the composition in an attempt to reduce the water content, however, resulted in loss of H.sub.2 O.sub.2 from the complex, forming a brittle, transparent, gummy, amorphous product of non-reproducible consistency. The resultant hard, brittle chips had a variable H.sub.2 O.sub.2 content ranging from about 3.20 to 18.07% by weight, depending upon the drying times.
The Shiraeff aqueous PVP--H.sub.2 O.sub.2 complex did not attain commercial success because (1) the product could not be handled easily because it was not a free-flowing powder; (2) its water and peroxide content of a desired peroxide compound varied over a wide compositional range; (3) the complex had product stability problems; and (4) the laboratory process of preparation could not be scaled up.
An object of the invention is to provide an anhydrous complex of PVP--H.sub.2 O.sub.2 for reducing the microbial content of surfaces.
Another object of the invention is to provide formulations of anhydrous complexes of PVP--H.sub.2 O.sub.2 for commercial applications.
Another object of the invention is to provide a method for reducing the microbial content of surfaces with a microbial amount of an anhydrous complex of PVP-H.sub.2 O.sub.2 having an H.sub.2 O.sub.2 activity of at least 3%, and, preferably, a molar ratio of PVP to H.sub.2 O.sub.2 between about 2:1 and 1:1, respectively, corresponding to an H.sub.2 O.sub.2 content of about 13 to about 24% by weight.